Robert abbott hadfield



' ganese is high as in steel of the kind known ROBERT ABBOTT HADFIELD, OF WESTMINSTER, ENGLAND.

MANUFACTURE OF MANGANESE STEEL.

No Drawing.

To all whom it may concern:

Be it known that I, Sir ROBERT ABBOTT HADFIELD, Bart, F. R. S., a subject of the King of Great Britain and Ireland, residing at WVestminster, England, have invented Improvements in or Relating to the Manufacture ,of Manganese Steel, of which the following is a specification.

This invention relates to the manufacture of steel of the kind comp-rising as its main constituents iron, manganese, carbon and silicon, and in which the proportion of manas manganese steel.

In the manufacture of manganese steel it has heretofore been usual to add ordinary ferro-manganese containing about 80% manganese to decarbonized and desiliconized iron in such proportion that, after allowing for a certain amount of oxidation, the resulting manganese steel contains usually about 11% to 14 per cent. of-manganese, the carbon present amounting to about 1.2- to 1.4 per cent. and silicon beingusually kept as low as possible, very seldom exceeding about .25 to .3 per cent.

Now the present invention has for object to produce a manganese steel possessing qualities that will render it, particularly when in the form of plates or sheets, better adapted for some purposes, particularly as a protective material against bullets, pieces of shrapnel and like missiles, than ordinary manganese steel.

Now I have found that this desirable object can be attained by increasing the percentage of silicon in the steel by purposely adding silicon to the materials used for making manganese steel. Good Yesults can be attained with the silicon within the limits of from about .65 to 2.5% the carbon being within limits of from about .90 to 1.25% and manganese within the limits of from about 10 to 17%. The new product seems somewhat tougher with lower carbon and yet its hardness is not so much or only slightly reduced by the lower percentage of carbon.

The carbon may however in some cases be increased to a higher percentage, say for example to 1.5% or even to 2%, especially when the steel is not to be rolled but used inthe form of castings, and it may be reduced to .75% or even lower. The lower limit of carbon resent in the new steel is however not con ned to the percentage mentioned but the upper limit should not exceed Specification of Letters Patent.

Application filed August 10, 1917.

Patented July 22, 1919.

Serial No. 185,521.

about 2% and will usually be much lower. The percentage of carbon is therefore comparatively low compared with the manganese as in ordinary manganese steel. The main feature of the new steel is the presence therein of a relatively high percentage of silicon as compared with ordinary manganese steel of commerce. steel, which may be called for distinction, high silicon manganese steel, is found, after being specially toughened in the manner usually adopted for toughening manganese steel, namely by heating it to a high temperature and quenching it in water, to possess greater toughness and resistance to perforations than ordinary manganese steel and therefore when rolled into plates or sheets, to offer greater resistance to perforation by bullets and other missiles than ordinary manganese steel of the same thickness.

The toughening of the new steel may be effected by heating it to a temperature say for example of about 900 C. and up to, it may be, about 1050 (l, or even above but Such a manganese W below its melting point and quenching it in water.

The new or hi h silicon manganese steel can conveniently e produced by adding silicon to a mixture of iron and ferro-manganese which may be the ordinary 80% ferromanganese of commerce. The silicon may be added as such or in any other suitable or convenient form, as for example ferro-silicon or silicon spiegel, conveniently the lat ter, the proportion of the ingredients used being such as to produce a steel containing a high manganese content, say of the order of 10 to 17 per cent. about .6 to 2 percent. of silicon and about .75 to 2 per cent. of carbon. The resulting steel may be cast into ingots or other castings.

For many purposes, the new manganese steel may advantageously be rolled into the form of sheets or plates (hereinafter referred to as sheets), or rods, bars or wire, before or after being subjected to the toughening process referred to. If desired, the toughening process may be repeated. The new manganese steel can also be used for castin of any desired shape and be heat treate or not as may be required, according to the purpose for which it is to be used.

The following are given as examples of high silicon manganese steels according to the invention that have been found, after. being specially toughened as described and rolled into sheets to give satisfactory results silicon so as to increase the content thereof as a protective material for use in the conin the steel to about decimal six of one per struction of helmets, body shields and procent. to two decimal five per cent, heating tective armor for air craft namely: the resulting high silicon manganese steel to a hi h temperature below its meltin Fe C S1 Mn g a point and quenching it in water.

3 5%?? 3. The herein described process of producing steel of great toughness and resistance Aluminium may be added to the new steel. which consists in adding to manganese Or the silicon in the new manganese steel may be replaced in whole or in part by up to about two per cent, and from about aluminium which appears to be its equivalent ten to -seventeen per cent. of manganese, for some purposes, as for the purpose f silicon so as to increase the content thereof increasing the toughness of the resulting in th t l to about decimal sixof one perman anese steel and its resistance to peI' cent. to two decimal five er cent. casting foration. Thus, the neW Steel may COIltain the resulting high silicon manganese steel or alloy.

for example about equal parts of Silicon into an ingot, converting said ingot into a steel containing in addition to iron, carbon and aluminium, say for example .7 5% of desired shape and thickness by appropriate 5 each. The claims as hereunto appended means, heating the said steel to a high temwhile mentioning only silicon are to be unt r below its melting point and cooling derstood as covering such equivalent. it quickly.

The quality of the new manganese steel '4, Th h i d ib d ro of procan be further varied or improved by the ducing steel of great toughness and resistaddition thereto of another element such for ance hi h i t i ddi t ngan e example as chromium, nickel, cobalt, vanasteel containing in addition to iron, from dium, tungsten or titanium r 0f W 1 about decimal seven of one per cent. to two more of such elements the percentage of such per t, f carbon d f b t t n m element or elements employed eing Such seventeen per cent. of manganese, silicon so say for example from one half of one p as to increase the content thereof in the steel cent. to seven per cent. as to givethe varyto from about decimal six of one per cent. ing desired qualities to the resultmg steel to two decimal five per cent, converting the resulting high silicon manganese steel into One example of the neW Steel With a dla thin body, heating the said body to a high tion of chromium that has been found to temperature below its melting point and afpossess excellent qualities after toughening terward cooling it quickly. by heating and cooling as described and 5. The herein described process of prorolling into plate or sheet form is as folducing steel of great toughness and resistlows ance which consists in adding to manganese Fe C Si Mm steel containing in addition to iron from S4 O8'% 1.04% L427) 12 65% 31% about decimal seven of one per cent. to two I per cent. of carbon, and from about ten to It 15 to be understood that the use of the seventeen per cent. of mangenese, silicon so new manganese steels herinbefore described as to increase the content thereof in. the is not limited to the manufacture of sheets f r protectiv pu p a hey m y be found cent. to two decimal five per cent, convertuseful for various other purposes and in ing the resultinghigh silicon steel into a either the rolled or cast condition. sheet, heating such sheet to a high tempera- What Iclaim is ture below its melting point and quenching 1. The herein described process of proit in water. ducing steel of greattoughness and resist 6. As a new article of manufacture, ance which consists in adding silicon to and wrought manganese steel possessing great melting it with managanese steel so. as to toughness and resistance to perforation .and increase the content of silicon therein from containing iron with from about decimal about decimal six of one er cent. to two seven of one per cent. to one decimal five per decimal five per cent., heatlng the resulting cent. of carbon, from about ten to seventeen high' silicon manganese Steel 110 a ig per cent. of manganese and from about decperature below its melting point and afteri'mal six of one per cent. to about two deciward quenching it in water. mal five per cent. of silicon.

2. The herein described process of pro- 7. As a new article of manufacture, ducing steel of great toughness and resistwrought manganese steel possessing great ance which consists in adding to manganese toughness and resistance to perforation and steel containing in addition to iron, carbon containing iron with about one per cent. of up to about two per cent, and from about carbon, from about ten to fourteen per cent. ten to seventeen per cent. of manganese, of manganese and from about decimal six of one per cent. to onedeciinal six per cent. of silicon.

8. As a new article of manufacture, wrought manganese steel in sheet form posscssing great toughness and resistance to perforation and containing iron with from about decimal seven of one per cent. to one decimal five per cent: of carbon, from about ten to seventeen per cent. of manganese and from about decimal six of one per cent. to one decimal six per cent. of silicon.

S). As a new article of manufacture wrought manganese steel in sheet form possessing great toughness and resistance to perforation and containing iron with about one per cent. of carbon, from about ten to fourteen per cent. 01 manganese and from foration and containing iron with about one per cent. of carbon, about twelve to thirteen per cent. of manganese and from about dec- 1mal s1x ot one per cent. to one decimal five per cent. of silicon.

Signed at 22 Carlton House Terrace in the city of Westminster, England, this twelfth day of July 1917.

ROBERT ABBOTT HADFIELD.

Witnesses WILLIAM CRoss, LEONARD ROWLAND. 

